Steam-engine.



J. STUMPE.

STEAM ENGINE.

APPLIoATIoN FILED AUG. 6, 1910.

Patented June 4, 1912.

IHIII xmwN JOHANN STUMPF, 3F BERLIN, GERMANY.

STEAM-ENGINE.

Specification of Letters Patent.

i Application filed August 6, 1910. Serial No. 575,921;

To all whom it may concern.'

Be it known that I, JOHANN STUMPF, a subject of the King of Irussia, and resident of 33 Kurfrstendamm, Berlin, Germany, professor, have .invented certain new and useful Improvements in Unidirectional-Flow Steam-Engines, of which the following is a specification.

The present invention relates to improvements in steam engines of the type known as imi-directional flow steam engines, that is those engines in which the steam enters at the end of the cylinder and exhausts toward the center usually.throngh exhaust ports about the center of the cylinder and controlled by the piston. The steam in such engines once it enters the cylinder never returns on its path within the cylinder and hence the name uni-directional 'flow steam engine.

The object of this invention is to provide improved means for controlling the commencement of compression without disturbing the uni-directional How of the steam. By means of this invention, the compression is not made dependent u on the covering of the exhaust ports by the piston and the method herein adopted, viz., retaining the uni-directional iow of the steam, voids condensation of the working steam on cold surfaces which have been swept over by exhaust steam.

According to this invention a uni-directional flow steam engine is provided with means for controlling the commencement o1 compression while minimizing surface condensation, said means comprising essentially, a hollow piston, an exhaustvalve lin said piston, means for operating said exhaust valve from a moving part of the engine to admit exhaust steam to said hollow piston and means for withdrawing steam from said hollow piston.

It is important to notice that the above recited means simultaneously effectthe two purposes of controlling the commencement of compression and minimizing surface condensation.

Another object of the present invention is to enable the adjustment to the supplementary exhaust valve in the piston so as to vary the point of release as desired or reverse the engine while still retaining the advantage of operation on the uni-directional principle.

The details of this invention will be further understood from the following descrip. tion of the forms illustrated by way of ex- Patented J une 4, 1912. i

ample in the accompanying drawings and the novelty of the invention-'is pointed out in the claims.

In the drawings -Figure 1, is a sectional side elevation through part of the cylinder and the engine frame of a horizontal uni-4 directional iow steam engine according to this invention. Fig. 2, is a section on the line 2-2 of Fig. 1. Fig. 3, is a section on the line 3-3 of Fig. 1. Fig. 4, is a hypothetical pressure volume diagram from the engine showing one method of using it.

Referring to Fig. 1, boiler steam enters by the inlet 3a, to a hollow cover 3b, which performs the double function of a steam chest and a hot jacket. This steamv is admitted past a valve 3, to the cylinder 1, the valve being operated from a moving part of the engine in any well known manner. In the cylinder 1, there is a piston 4, which in its travel controls exhaust ports 2, in the cylinder walls. In this engine steam enters at 3a, and is cut 0E after the piston has completed a suitable part of its stroke.v After cut ofi', thesteam expands while pushing the piston to the left and in expanding the steam of course does work until the pist-on 4, uncovers the exhaust ports 2, when the steam passes out to the annular chamber Qa, and thence by the outlet 2b, into a condenser or other apparatus not further illustrated. It will be seen that the steam does not at any time return on its path in passino' from the inlet to the exhaust at the end ofj the cylinder steam space. In this way, as is known, the hot steam is not brought in contact with cold walls and the steam is graduated in zones of driest steam at the inlet 3, and wettcst steam near the outlet. The dryness of the steam near the inlet is accentuated by the hot jacket formed by the hollow cover 3b.

On its return stroke the piston covers the exhaust ports 2, at an early stage and in ordinary uni-directional flow steam engines, the steam is compressed for the remainder/. of the lreturn stroke. This compression usually lasts for about of the stroke. It will be understood that Vin many instances this compression will be excessive. The present invention is designed to relieve this excessive compression while minimizing sur- I face condensation by leaving the steam more or less quiescent at the inlet end and withdrawing steam through the hollow piston.

-of steam at the inlet end. This is because the steam passing through the valve is drawn always from the zoneslocated nearest to the piston so that there is no iow of cold steam over the surfaces at the inlet end which come in contact with the hot working steam at the next stroke.

In the particular form of the invention illustrated a composite valve formed of two parts 8, and 8, is, provided with oppositely handed internal threads 8b, adapted to engage with oppositely handed threaded parts 17 and 17 on a rod 9, which passes out through the cylinder at 9, and is rotatably mounted at 9", in a slide 10. The slide 10, is guided in the bottom slide of the crosshead 5, and carries in turn a slipper 10', with which a ball end 12, on an arm 12 engages. The arm 12', is eccentric to the crosshea-d pin 52, and is conveniently in the form of a projecting arm at right angles to the connecting rod. On the rod 9, there is carried a toothed wheel 20, which is adapted in one of the end positions of the crosshead Y to be moved into engagement with the rack 21, which may in' turn be moved by any suitable means as for instance a motor cylinder 22.

The parts 8 and 8a, of the composite valve are waisted so as to permit the passage of steam to the center of the hollow piston as indicated by the arrows. In the bored out part of the hollow piston there are cutting olf edge 16 and 14', which are arrange to coperate with cutting off edges 14 and 16 of the valve.

By rotating the valve rod 9, the relative positions of the cutting off edges of the valve and casing are altered so that the point of release and the commencement of compression may be thereby varied as is well understood in this art. Also in the extreme, the valve parts 8 and 8a, may be brought so closely together that only the cutting ofi' edges 16', are used in which case the engine will be in position to reverse as will be readily understood, since the parts S, would then open the passage from the rear side of the pist-on to the interior thereof. The parts are illustrated with the piston at the mid point of itsstroke.

The hollow piston 4, has an inset wall 42, of the form seen in Fig. 2, and this wall has 'openings 43 therein. The inset part of the piston and the openings 43, thus form a communicating passage between the interior of the piston and the main exhaust ports 2, and thereby enable the steam passing' the valve 8, 8, to exhaust to the main exhaust ports 2, and thence to the condenser.

Referring to Fig. 4, it will be seen that if desired t-he release of residual steam through the valve 8, 8a, may be controlled in such a way that the steam is only released after it has been compressed for a suitable period. This enables the steam passed to the hollow piston to be used, if desired, in accessory apparatus. As shown in Fig. 4, the main exhaust is opened at e', and closed at e2. The piston 4, has then just covered the ports 2, and compression proceeds till the point z3, is reached when the valve S, 8, is timed to open. The steam'exhausts from the cylinder space from z3, to z, into the hollow piston 4, and from the piston it may pass to the exhaust as illustrated or it may be supplied to accessory apparatus. Of course the valve 8, 8a, may be timed to open just before the main ports 2, are closed by the piston in which case the indicator diagram would resemble that of an ordinary engine.

The valve 8, 8a, it will be seen, is illustrated as a non-balanced piston valve. It could, however, be equally well arranged as any other type of valve. By means of a non-balanced piston valve and the arrangement of operating gear illustrated, the following important result is obtained; when the crank is in the dead position, the arm 12, is vertical and if steam is admitted into the cylinder, the valve 8, 8a, is pressed in one or other directiony and a force is transmitted to the connecting rod tending 4to help the crank past the dead center. This action is of use in starting the engine and it is also valuable during ordinary running as it enables the weight of the flywheel to be reduced.

I claim- 1. In combination with the moving parts of a steam engine, a cylinder having a steam inlet port at its end and separate exhaust ports, a mechanically actuated inlet valve controlling said inlet port, a hollow ported piston working in said cylinder and arranged to overrun said exhaust ports at and near the end off its stroke, the port in said piston being arranged to register with said cylinder exhaust ports when the piston has overrun the same, and means for controlling the commencement of compression while minimizing surface condensation, consisting of a valve on said piston and controlling the admission of exhaust steam to the interior thereof, and means actuated from a moving part of the engine for operating said valve.

linletport at its end mizing surface condensation,

and separate exhaust ports, a partial hot jacket about the inlet end of said. cylinder, a hollow ported piston working in said cylinder and arranged to overrun said exhaust ports at and near t-he end of its stroke, the port in said piston being arranged to register with said cylinder exhaust ports whenthe pistonhas overrun the same, and means for controlling the commencement of compression while miniconsisting of a valveon said piston and controlling the admission of exhaust steam to the interior thereof, and means actuated from a moving part of the engine for operating saidvalve.

8. In combination with the moving parts of a uni-directional flow steam engine, a cylinder having an inlet port at its end used only for admitting steam and separate exhaust ports, a hollow piston adapted to overrun and control said exhaust ports, in the cylinder at and near theend of its working stroke, and means for controlling the commencement of compresslon while minimizing surface condensation, consisting of a valve cn said piston and cont-rolling the admission of exhaust steam to the interior thereof, means actuated from a moving part of the engine for operating said Valve and means for withdrawing exhaust steam from said hollow piston.

4. In combination with the moving parts of a uni-directional flow steam engine, a cylinder having an inlet port at its end used only for admitting steam, and separate exhaust ports, a hollow piston adapted to overrun and control said exhaust ports in the cylinder at and nearthe end of its working stroke, an adjustable valve on said piston, and controlling the admission of exhaust steam to the interior thereof, means for controlling the commencement of compression while minimizing sur-face condensation consisting of means actuated from a moving part of the engine for operating said'vvalve, and means for withdrawing exhaust steam from said hollow piston.

5. In combination with the cross head and connecting rod of a uni-direct-ional fiow steam engine, a cylinder having a steam inlet port at its end, a hollow piston in said cylinder, and means for controlling the commencement of compression while minimizing surface condensation, consisting of an unbalanced piston valve slidahle in said hollow piston and controlling the admission of exhaust steam to the interior of the piston,

an arm set eccentrically on the cross head end of the conecting rod, a rod joining said piston valve and said eccentric arm to operate said piston valve, and means for withdrawing steam from the interior of the piston. i

6. In the combination with a cylinder, having an inlet lport at its end and a separate exhaust port, means for maintaining graduation of the steam in zones of driest steam at the inlet end and wettest steam near the exhaust ports, consisting of a hot jacket at the inlet end of the cylinder, a hollow piston adapted to uncover said exhaust ports near the end of its working stroke and having a port registering for part o the travel of the pistonv with the cylinder exhaust port, and anopening at t-he end, an exhaust valve on said piston for controlling said opening andV means actuated from a moving part of the engine for operating said valve.

7 In combination with a cylinder having an inlet port at its end and a separate exhaust port, means tion of the steam in zones of driest steam at the inlet and wettest steam near the exhaust ports, consisting of a hot jacket at the inlet end of the cylinder, a hollow piston adapted to uncover said exhaust ports near the end of its working stroke and having a port registering for part of the travel of the piston with the cylinder exhaust port and an opening at the end, an adjustable exhaust valve on said piston for controlling said opening, and means actuated from a moving part of the engine for operating said valve.

8. In combination with a cylinder, having an inlet port at its end, and a separate exhaust port, lneans for maintaining graduation of the steam in zones of driest steam at the inlet and wettest steam near the exhaust ports, consisting of hot jacket at the inlet end of the cylinder, a hollow piston adapted to uncover said exhaust ports near the end of its working stroke, and having a port registering for part of the travel of the piston with the cylinder exhaust port, and an opening at the end a reversing exhaust valve in said piston for controlling said opening and means actuated from a moving part of the engine for operating said valve.

In witness whereof I have hereunto set lmy hand in the presence of two witnesses.

JOHANN STUMPF. lVitnesses JULIUS MAEMECKE, FRANK DEISSLER.

for maintaimng gradua-l 

